Mining equipment, such as large mining excavators (e.g., shovels, draglines, etc.) typically use relatively large AC and/or DC motors to power the movement of the equipment and/or the movement of material. These motors can include propel motors, hoist motors, swing motors, crowd motors, and/or drag motors, etc. Such motors are typically powered by conventional DC or AC electric drive systems. For example, conventional DC electric drive systems typically use AC-powered rotating Motor-Generator (M-G) sets or static variable speed drives with thyristor rectifiers to change the speed and torque of a DC motor.
Some consider the M-G set systems to be outdated technology, as not energy efficient, and/or as requiring high levels of maintenance. The static DC systems can require switched capacitor banks and/or reactors to provide an acceptable system power factor and/or harmonic filters to pass the harmonic limit requirements set by the electrical power utility. This additional equipment can require space and increase capital costs without contributing to the machine's capacity to move material.